Oesophagus Physiology Flashcards
First phase of swallowing
Oral = Voluntary
Second phase of swallowing
Pharyngeal = involuntary
Third phase of swallowing
Oesophageal = involuntary
Oral Phase two sub-phases
Preparatory = Mastication, mechanical digestion -> bolus
Transfer = Bolus propelled into pharynx
Physiological change during oral phase
Tounge closes off anterior oral cavity = bolus pushed to back of mouth
Physiological change during pharyngeal phase
Bolus peristalsised down the pharynx
Soft palate elevates = seals upper airway
Epiglottis swings down = seals lower airway
Oesophageal Phase
Upper oesophageal sphinchgter relaxes = bolus in oesophagus
Nervous control of swallowing
Swallowing centre in medulla
Primary Peristalsis is
Induced by swallowing - contraction above bolus, relaxation below bolus
Secondary peristalsis is
Not induced by swallowing, stimulation of oesophageal sensory receptors wanting to get stuff out of there (can also be acid going back up)
Lower Oesophageal Sphinchter muscle type
Smooth
Lower oesophageal sphinchter cell type change
Squamous -> columnar (squamocolumnar junction)
GORD
Gastro-oesophageal reflux disease
Transient Relaxation of Oesophageal Sphinchter
Transient = not when food trying to get in
Occurs normally to let air in
Bad if happens too often as GORD from acid
Causes of GORD
- High acid in fundus
- Hiatus hernia = easy for acid to get into oesophagus
- Impaired oes. Peristalsis = cant clear the acid
- LOS not tight (from eg alcohol )
